Method of making stable low pour point lubricating oils



Patented Feb. 7, 1933 UN I TED Parent OFFICE HARRY T. BENNETT AND LE ROY G. STORY, OF TULSA, OKLAHOMA, ASSIGNORS, BY

DIBEC'I AND MESN'E ASSIGNMENTS, TO MID-CONTINENT PETROLEUM CORPORA- TION, F TULSA, OKLAHOMA, A CORPORATION OF DELAWARE METHGD OF MAKING STABLE LQW POUR POINT LUBRIGA'IING- OILS No Dramas. original application filed. Gctober 24, 1927, Serial Nb. 228,487. lnivided and this application filed July $3, 1923. Serial No. 294,933. Renewed April 17, 1931.

This invention relates to methods of making stable low pour point lubricating oils. This application is a division of an application for patent on lubricating oils and methods of making the same, filed by us on Oct.

24:, 1927, Serial Number 228,487, Patent Number 1,806,735, issued May 26, 1931.

One of. the objects of the invention is to lower the pour point without impairing the lubricating properties of the oil.

Another object is to obtain and maintain the low pour point. In other words, this object is to produce a lubricating oil having a stable, or fixed, low pour point which is not changed by exposure to the extremes of high and low atmospheric temperatures. This object may be attained by mixing the composition at a high temperature, as will be hereafter described.

A further object is to produce a low pour point lubricating oil without causing an objectionable change in the color of the oil.

A still further object is to accomplish these results by lowering the pour point without changing the viscosity of the oil.

With the foregoing and other objects in view, the invention comprises the novel method hereinafter specifically described to set forth an embodiment of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications which come within the scope of the claims hereunto appended.

Briefly stated, we prefer to lower the pour point by adding to alubricating oil a quantity of soap small enough to accomplish this re sult without materially changing the viscosity of the lubricating oil. This quantity preferably ranges between five-hundredths percent and three-tenths percent of the weight of the mass, and in actual practice we have found that one-tenth percent gives highly satisfactory results. However, as will be hereafter pointed out, there is a further problem involved in maintaining or stabilizing the low pour point. We have shown how this can be accomplished by the use of relatively high temperatures in the treatment of lubricating oils that will withstand such tem-,

0 peratures. A further advantage may be obtained by adding a small percentage of animal oil, or vegetable oil, as will be hereafter described.

In our early efforts to lower the pour point of a paraffin base lubricating oil, withoutfifi changing its viscosity, we found that the addition of very small percentages of soap, as heretofore mentioned, would produce the desired result for a more or less limited period. For example, we have prepared oils which showed pour points of -l0 F. but after exposure to weather temperatures ranging from +80 F. to 20 F., the pour point tended to rise and after long periods some oils even reverted to the original pour point of about 15 F. to +35 F. We discovered, however, that in those cases wherein the pour point was unstable, the oils had been prepared by mixing the soap in the oil at temperatures below 300 F., whereas in every case in which the soap had been mixed with the oil at temperatures in excess of 300 F. the pour point was very stable.

For the preparation of low pour point oils wherein the consistency is such that high temperatures are advantageous, or cause no serious damage, we heat the oil to temperatures preferably in excess of 300 F.,' for example, 300 to 350 F., for the step of commingling the soapin the oil. 8 While the oil, is at a temperature between 300 and 350 F. we prefer to gradually mix thepure soap with the oil, and to violently agitate the massuntil the mixture is uniform. In this way a stable material is obtained.

Lubricating stocks from paraflin base crudes are derived from wax distillate or that fraction of the crude coming from the still after the lower boiling point products such as gasoline, naphtha, kerosene and gas oil have been removed by fractional distillation The wax distillate is essentially a mix ture of paraffin wax and lubricating stock from which it is extremely diflicult to remove a suflicient amount of wax to give a lubricant of pour point of 0 F. In our process it is not necessary to remove all of the wax from the oil, but only the major portion. We treat the remaining oil and wax mixtureto produce a stable low pour point product.

ing oil heated to 300 to 350 F.

A clearer understanding of our invention may be obtained by a more specific description of the details of one form of the invention. v

5 A, 'wax distillate, having a pour point of 50 to-100 E, is chilled until the major portion of the wax has separated, and the cold mixture is forced under pressure through a filter to removethe separated wax. The

filtered oil or pressed distillate, having a pour point of to F., is then separated by distillation into lubricating stocks having the same pour point and aviscosity of 90 to 1000 seconds Saybolt at 100 F., depending on 15 theade of lubricant desired.

T e lubricating stock is then bleached, by any of the well known methods of decolorization, such as the use of acid and clay, to the desired color, and the resultin lubricat- Zbout onetenth percent of aluminum stearate in the form of a jell, is then-thoroughlyincorporated in the oil. The product has a pour point of 0 to '-20F., and is extremely stable to changing temperature conditions. In some cases it is desirable to add to the composition a small quantity of. animal or.

vegetable oil, and we have found it advantageous to add such oils as neats-foot oil or 30 castor oil in proportions of 2 to 10 percent of the weight of themass, about 4 percent being preferable.

It is to be understood that-we do not limit ourselves to the above example. Other soaps as well as aluminum stearate, such as alu-,

minum palmitate, zinc stearate, zinc palmitate, etc., have given good results in amounts from five-hundredths of one per cent to three tenths of. one percent.

Reco points is provided in Technical Paper 323B, U. S. Government Specification No. 2d, Department of Commerce Publication, U. S.

Government Master Specification for Lubri 5 cants and Liquid Fuels and Methods for.

5 Sampling and Testing, on pages 40 and 41' point lubricating oils which consists in heatmgia lubricating oil composition to 300 to 350 F., and while thus heated mixing therein about one-tenth percent aluminum starate and thereby producin a stable oil of lower pour point than the oil treated without materially affecting the viscosity thereof.

ized procedure of determining pour' 3. The method of makin stable low our oint lubricating oils whic comprises c illmg wax distillate until the major portion of of lower pour point t an the oil treated with-. out materially affecting the viscosity thereof.

4. The method of making stable low our point lubricating oils which consists in 0 illing wax distillate until the major portion of, the wax has crystallized, separating such portion of the'wax necessary to give a dewaxed distillate of pour point 15 to 35 F., distilling said distillate 'to produce a lubricating stock having a viscosity of 90 to 1000 seconds Saybolt at 100 F., treating said stock to such color that temperatures herein specified cause no apparent darkening, heating the oil to 300 to 350F., and while thus heated mixing therein one-tenth percent aluminum stearate and thereby producing a stable oil of lower pour point than theoil treated without materially affecting the viscositythereof.

5. The method of making stable low pour oint lubricating oils which consists in heat- 1ng a lubricating oil of 90 to 1000 seconds and thereby producing a stable oil of lower Saybolt at F., and containing 2 to 10 I pour point than the oil treated and without 1 affecting the viscosity thereof.

6. The method of making a stable low pour point lubricating oil which consists in removmg a portion of the wax from the oil, treating the partially dewaxed product with soap while the oil is undergoing heat treatment.

and thereby producing a stable low pour point oil having a lower pour point than the original oil without materially afl'ecting the viscosity thereof. 7 I

v In testimony that we claim theforegoing we hereunto afiix our signatures.

. HARRY T. BENNETT. LE ROY e. STORY. 

